CMU Block Wall for Retaining Liquid

[psychedomination]

Hi there,

I am designing a low wall to temporarily contain water, which will fill infrequently. The height of the wall will be 20". Typically I would go for a reinforced concrete wall when considering a liquid retaining structure but due to the wall being so short I was thinking of going the CMU block wall route with a suitable swellable waterbar and a thick render on the water facing side of the wall with a Xypex waterproofing agent. Due to the height, the water pressure is quite small. Using CMU should be faster and cheaper to construct.

I found some guidance on a detail for this system following the CIRIA guidelines in the "Masonry Bunds for Oil Storage Tanks.

See below typical details that I would most likely adopt (main difference is that I would have the vertical rebar post installed into the existing slab with straight embedment only and I will use an expanding water stop) :

However, I would like some advice on how to detail the connection between the new bund wall tying into the existing reinforced concrete block wall. Normally I would key the new wall into the existing but I'm not sure how this interface would work with a water stop. Instead of keying in, would it be a better detail to put in a post installed rebar dowels to connect the new bund to existing wall? Ideally, I don't really want to disturb the rebar in the existing wall much.

Any advice on an optimal detail in the situation to provide a waterproof joint with an expanding waterstop would be helpful.

For context see image below :

 

[RPGs]

There's not a nice way to say this: that sketch you provided is extremely confusing. I do not see how that is an elevation. Could you try marking up a photo instead?

 

[psychedomination]

Hi RPGreen, apologies it is a bad sketch. I rushed it before heading off from the office. It's actually a section view and I notice that it is missing a line to show the end of the existing wall, which is probably adding to the confusion.

Essentially I was trying to portray something like shown below, where a new short CMU block wall butts up against an existing building wall at a 90 degree angle :

My question is whether keying into the existing wall or putting in post installed rebar dowels would be better for a water tight connection when using an expandable waterbar. The waterbar would need to extend vertically up the height of the bund wall (placed at the joint between the new wall and old wall face).

Any advice on an optimal detail for a joint like this (when considering water tightness) would be greatly appreciated.

 

[HTURKAK]

Mr. psychedomination ,

IMO,Keying to existing masonry wall, 2 coats of render finish etc seems not reasonable..

I will suggest you , lining the pool with UV resistant PVC membrane ..

Write PVC MEMBRANE LINING POOL and search for local suppliers at your zone ...

e.g.

https://membraneconcepts.com/specifications/

Tim was so learned that he could name a
horse in nine languages: so ignorant that he bought a cow to ride on.
(BENJAMIN FRANKLIN )

 

[psychedomination]

@HTURKAK Thanks for your response : Just for clarity, I was not thinking of using a standard plaster finish alone. I was considering using either the following products with it:

Sika Seal 107 (

https://usa.sika.com/en/constructio...ntitious-waterproofing/sikatop-seal-107.html)

or

Although a PVC membrane would likely work too. Thanks for sharing.

 

[Enginerdad]

I'm going to parrot what @HTURKAK said. It seems like it would be simpler to add an independent waterproof liner rather then to try to make a naturally porous material waterproof. Not to mention that sheets of pool liner or similar are probably much cheaper than specialized masonry membranes.